WebRequest调用

WebRequest支持不同的浏览器对象，可以在底层使用不同的XMLHttpRquest方式调用Web服务。

Time.aspx

<%@ Page Language="C#" %>

<script runat="server">
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        Response.Write(DateTime.Now.ToUniversalTime());
    }
</script>

CallTimeWebRequest.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CallTimeWebRequest.aspx.cs" Inherits="Chap9Project.CallTimeWebRequest" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">
        function pageLoad() {
            var webRequest = new Sys.Net.WebRequest();
            webRequest.set_url("Time.aspx");

            webRequest.add_completed(completedHandler);
            webRequest.invoke();
        }

        function completedHandler(result, eventArgs) {
            if (result.get_responseAvailable()) {
                alert(result.get_statusText());
                alert(result.get_responseData());
            }
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
    </div>
    </form>
</body>
</html>

WebRequest默认请求方式是GET，可以使用POST上传数据。

EchoABC.aspx

<%@ Page Language="C#" %>

<script runat="server">
    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        if (Request.Form["abc"] != null) 
        {
            Response.Write(Server.HtmlEncode(Request.Form["abc"]));
        }
    }
</script>

SetVerb.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>NetWorking</title>
    <script type="text/javascript">
        function pageLoad() {
            var webRequest = new Sys.Net.WebRequest();
            webRequest.set_url("EchoABC.aspx");
            webRequest.set_httpVerb("POST");
            webRequest.set_body("abc=123");
            webRequest.add_completed(completedHandler);
            webRequest.invoke();
        }

        function completedHandler(result, eventArgs) {
            if (result.get_responseAvailable()) {
                alert(result.get_statusText());
                alert(result.get_responseData());
            }
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
    </div>
    </form>
</body>
</html>

WebRequest对象还可以设置超时限制。

TimeOut.aspx

...

function pageLoad(){
  ...
  webRequest.set_timeout(5000);      
}

function completedHandler(result, eventArgs){
  if(result.get_timeOut()){
   ...
   } 
   if(result.get_responseAvailable()) {
   ...
   }  
}

WebRequset传递额外数据

UserContent.aspx

...

function pageLoad(){
  ...
  webRequest.set_userContext('send this data to the callback');
}

function completedHandler(result, eventArgs){
   if(result.get_responseAvailable()) {
       var userContext = result.get_webRequest().get_userContext();
   }  
}

WebRequest获取即将发出的请求的完整的URL

WebRequest.getResolvedUrl()
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原文地址：https://www.cnblogs.com/hellolong/p/3989947.html